How to check last character in command line arguements?

Question

So im trying to count the number of files in the command line, heres what ive got so far

# include <stdio.h>
# include <stdlib.h>

int main(int argc, char* argv[]){
int cCount = 0;
int cHeadCount = 0;
int objCount = 0; 
int makeCount = 0;
int othCount =0;

for(int i = 1; i< argc; i++){
    /*
    if argv[i] last char is c 
        cCount++;

    if argv[i] last char is h 
        cHeadCount++;

    and so on for the rest

    */
printf("C Source: %d\n", cCount);
printf("C Header: %d\n", cHeadCount);
printf("Object: %d\n", objCount);
printf("Make: %d\n", makeCount);
printf("Other: %d\n", othCount);
}

so if you type in something like $ ./fm main.c main.o sub.c sub.o you should get

C source: 2
C header: 0
Object: 2
Make: 0
Other: 0

What i need help is the if statements inside the for loop. BTW is the for loop correct? Is there a function that will return the last character of a string? From what Ive seen, I dont seem to recall one but I could be very wrong.

If im going about this wrong, or on right track, please tell me. Any help appreciated.

EDIT:

Heres what I have inside the for loop:

for(int i = 1; i < argc; i++){
    int len = strlen (argv[i]);

    if ((argv[i][len - 2] != '.') ){
        if((strcmp(argv[i], "Makefile")==0) || (strcmp(argv[i], "makefile")==0)){
        makeCount++;
    }else{
        othCount++;
        continue; //if i take this out, it counts `other` objects wrong too
    }
    }

    if(argv[i][len - 1] == 'c'){
        cCount++;

    }

    else if(argv[i][len - 1] == 'h'){
        cHeadCount++;

    }

    else if(argv[i][len - 1] == 'o'){
        objCount++;

    }

    else {
        othCount++;           
    }       

}

So the problem now is that its not recognizing makefile s as a Makefile. It counting them as Other . So where I should have say 5 Makefile s and 10 Other files, its saying i have 0 makefiles and 15 Other files. c , h and o files work/count fine. Any help appreciated

Answer 1

You can use strlen() to determine the length of each string in argv. Knowing the length you should be able to peak at the last element in the array.

NOTE: I won't write the code for your homework assignments.

Answer 2

You can use string function strlen which calculates the length of string and to use this you have to include header <string.h> . And from that you can check the last index of every word of command line argument that which condition it satisfies , like

for(int i = 1; i< argc; i++){
        int l=strlen(argv[i]);
    if(argv[i][l-1]=='c')
        cCount++;
    else if(argv[i][l-1]=='h')
        cHeadCount++;
    else if(argv[i][l-1]=='o')
        objCount++;
    else if(argv[i][l-1]=='m')
        makeCount++;
    else othCount++;


   }

Answer 3

You can use switch statement to do this:

# include <stdio.h>
# include <stdlib.h>
# include <string.h>

int main(int argc, char* argv[]){
        int cCount = 0;
        int cHeadCount = 0;
        int objCount = 0;
        int makeCount = 0;
        int othCount =0;
        int len = 0;

        for(int i = 1; i< argc; i++){
                len = strlen (argv[i]);
                /* Assuming that any argv (filename) which either 
                 * do not have any extension or extension of 
                 * more than 1 character goes under "other" file catagory
                 */
                if (len > 2 && (argv[i][len - 2] != '.')){
                        othCount++;
                        continue;
                }
                switch(argv[i][len - 1]){
                        case 'h':
                                cHeadCount++;
                        break;
                        case 'c':
                                cCount++;
                        break;
                        case 'o':
                                objCount++;
                        break;
                        case 'm':
                                makeCount++;
                        break;
                        default:
                                othCount++;
                        break;
                }
        }
        printf("C Source: %d\n", cCount);
        printf("C Header: %d\n", cHeadCount);
        printf("Object: %d\n", objCount);
        printf("Make: %d\n", makeCount);
        printf("Other: %d\n", othCount);
        return 0;
}

The output of the program:

$ ./fm main.c main.o sub.c sub.o
C Source: 2
C Header: 0
Object: 2
Make: 0
Other: 0

Answer 4

Use strrchr like this

#include <stdio.h>
#include <string.h>

int main(int argc, char* argv[]){
    int cCount, cHeadCount, objCount, makeCount, othCount;
    cCount = cHeadCount = objCount = makeCount = othCount = 0;

    for(int i = 1; i < argc; i++){
        char *filename = strrchr(argv[i], '/');
        filename = filename ? filename + 1 : argv[i];

        char *ext = strrchr(filename, '.');
        if(strcmp(filename, "Makefile") == 0 || strcmp(filename, "makefile") == 0){//or use strcasecmp ?
            ++makeCount;
        } else if(ext == NULL) {
            ++othCount;
        } else if(ext[1] == 'c' && ext[2] == 0){
            ++cCount;
        } else if(ext[1] == 'h' && ext[2] == 0){
            ++cHeadCount;
        } else if(ext[1] == 'o' && ext[2] == 0){//or strcmp(ext, ".o")==0
            ++objCount;
        } else {
            ++othCount;
        }
    }
    printf("C Source: %d\n", cCount);
    printf("C Header: %d\n", cHeadCount);
    printf("Object: %d\n", objCount);
    printf("Make: %d\n", makeCount);
    printf("Other: %d\n", othCount);
}